Acquired Immunodeficiency Syndrome (AIDS) is known to produce several clinical manifestations in the eye as well as in various other parts of the central nervous system. However, the optic nerves fro patients with AIDS have not been systematically evaluated either clinically or histopathologically. REcent investigations in our laboratory provide preliminary evidence that optic nerves obtained from AIDS patients have diminution of axons compared to age-matched controls. This axonal loss did not appear to correlate with the use of certain medication regimens. We will utilize the PPD method for identifying degeneration in the optic nerves of patients with AIDS on various treatment modalities and HIV+ and HIV- age-matched controls. The distribution of this degeneration could lead to insights regarding the nature of the lesion and efficacy of treatment. Additionally, the PPD method in conjunction with our computerized image enhancement system permits us to do quantitative analyses of total fiber counts, and the nerve fiber spectrum. The extent and distribution of degeneration in intracranial optic nerve can be compared to degeneration in retrobulbar optic nerve and retinal to help ascertain to what extent AIDS related degeneration in the optic nerve is primary or consequent to nerve fiber layer infarcts from retinal manifestations of the disease. The pattern and extent of degeneration of the optic nerves can then be compared with the clinical impairments associated with optic nerve disease in AIDS patients. Such clinical impairments may be detectable in AIDS Related Complex (ARC) or other HIV+ patients in the absence of obvious symptoms.